The Hiroshima High Court on September 25 agreed with Shikoku Electric Power Company (YONDEN)'s objection and reversed a provisional injunction against the restart of operations of the No.3 reactor at the YONDEN Ikata nuclear power plant (Ikata Town, Ehime Pref.).

The decision aroused concern and anger from local residents, paving the way for the utility to resume operations of the reactor as early as late October.

In the trial, a major issue concerned the possibility of a large-scale eruption that may or may not occur at a caldera volcano located 130km away from the plant.

The previous court decision made in December last year strictly applied the Nuclear Regulation Authority's volcano impact assessment guidelines, taking into consideration the possibility that pyroclastic flows triggered by an eruption could reach the plant premises.

In contrast, the decision this time considered that the contents of the NRA volcano guidelines themselves are irrational and concluded that the location of the NPP is not inappropriate unless the probability of a large-scale eruption is "demonstrated based on scientific evidence".

However, in regard to the probability of a major volcanic eruption, the present perspective "can neither assess precursor phenomena accurately nor take a concrete precaution in advance". In sum, the latest decision imposed an impossible demand on plaintiffs that the likelihood of occurrence of a major volcanic eruption which is difficult to predict must be "shown based on scientific evidence".